Apparatus for basing incandescent lamps and similar articles



May 23, 1933. K WRIGHT 1,911,046

APPARATUS FOR BASING INCANDESCENT LAMPS AND SIMILAR ARTICLES Filed March 51, 1925 Invenl'or: Danie\ KMi'righi',

His Attorney Patented May 23, 1933 UNITED STATES PATENT orriee DANIEL K. WRIGHT, OF PATERSON, NEW JERSEY, ASSIGNOR '10 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK APPARATUS FOR BASING INCANDESCENT LAMPS AND SIMILAR ARTICLES Application filed March 31, 1526.

My invention relates to the basing of in candescent lamps and similar articles in which a metal shell or ring is cemented to a glass bulb by means of basing cement hardened by baking at a temperature of several hundred degrees Centigrade, and more particularly to an improved method and apparatus for baking the basing cement.

A common practice at the present time is to base incandescent lamps and similar articles on a basing reel constructed to hold the bulb with the base in proper position on 1t and with a layer of basingcement between them, the base being seated in a metal socket.

5 A series of gas-burners mounted adjacent to the rim of the basing reel are so positioned that as the reel rotates each socket, with a base in it, is brought within range of gasburners which direct their flames on the socket and thereby heat the base in the socket to the proper temperature to bake the basing cement. To obtain good results the fires of the gas-burners must be carefully adjusted, and the comparatively large mass of metal which is heated during the basing operation requires considerable time to cool down to a temperature at which the based lamp can be removed from the basing machine, so that a reel of considerable diameter is required to give the necessary cooling time. The basing machines using gas-burners also radiate a great deal of heat, causing discomfort to the operators, particularly in warm weather.

One object of my invention is to provide an improved method of basing incandescent lamps and similar articles by baking the basing cement to the proper temperature without gas-burners, and with a minimum waste of heat. A further object is to provide a method of basing in which the temperature to which the cement is subjected can be controlled and regulated very accurately. A further object is to provide a simple and rugged apparatus by means of which my improved method of basing can be practiced commercially and on a large scale.

In accordance with my invention the basing cement for securing the metal shell or ring of the base to the glass bulb of the incandescent lamp or similar article is heated Serial No. 98,359.

to the proper basing temperature by heating the metal electrically by electricity applied to the shell or ring in any suitable way to develop in the metal itself the necessary heat. One convenient way of developing the necessary heat is to cause such a heavy flow of current to take place through the metal of the base that the metal acts as a resistance heater which bakes the basing cement. This current may. conveniently be supplied-by a step down transformer constructed to supply a secondary current of low voltage and high amperage. 'Another convenient way of developing heat in themetal of the base is to bring the base into inductive relation to a rapidly varying electromagnetic field, which may be produced by means of a coil placed over or in the vicinity of the base and energized from some suitable source of high frequency current. My invention may conveniently be practiced in a machine constructed in the form of a rotating reel provided with automatically controlled contact fingers which engagediametrically opposite points on the shell of the base to include the metal in circuit with the contact fingers and thereby heat the metal to the proper temperature for baking the cement. In such a machine embodying my invention the soldering of the leading-in wires to the shell of the base may be done conveniently and efficiently while the base is still hot from the basing operation.

My invention will best be understood in connection with the accompanying drawing in which merely for purposes of illustration I have shown one of the various forms of apparatus which may be used and in which Fig. 1 is a plan view of a basing machine constructed in accordance with and embodying my invention; Fig. 2, a plan view along the line 22 of Fig. 1; Figs. 3 and 4, diagrammatic views showing modified form of connections; Fig. 5, a diagrammatic view of a special form of transformer; and Fig. 6, a view illustrating the use of a high frequency coil for heating the base.

In the particular form of basing machine shown in the drawing a table 1 carries a vertical tubular center post 2 which forms the axis of the movable parts of the machine. I

Secured to the top of this center post is a stationary cam disc 3. A basing reel or spider l for carrying the bulbs and bases through a predetermined path is mounted on the table 1 to rotate about the center post 2 as a pivot. This spider is provided with resiliently mounted bulb cups 5 for engaging the ends of the bulbs of the incandescent lamps or similar de ices to which the bases are to be applied. Cooperating with each bulb cup is a base holding socket consisting of a pair base holding jaws (5 fixed to but insulated from the spider i and also insulated from each other. These jaws are recessed to form a socket into which the base 7 will fit snugly enough to be held firmly during the basing opera ion. The bulb S of the lamp with the base in position on it and a layer of basing cement between the bulb and the metal shell of the base is inserted in the machine by hand so that the base held by the jaws 6 and the bulb firmly pre sed into the base and held in bv the spring pressed bulb cup L are ins rted in the machine before the aws G reach the position B and are carried in the direction of the arrow through practically one complete revolution 01 the spider.

The ba es '7 inserted in the machine and held between the jaws 6 are heated to the proper temperature for baking the basing cement by electrically developing or generating in the metal shell of the base sutlicient heat either by conduction through the metal, or by curre -"s induced in the metal, the electrical resistance oi the metal being utilized to generate the necessary heat. In the particular examples shown in l to 5 inclusive, the heat developed in the metal of the base by passing through it a hea *y current of electricit y which due to the resistance of the base develops in the metal suiiicient heat to bake the basing cement. In the particular arrangement shown the current is conducted to the metal of the base shell by contact fingers 9 which engage the shell ot the base at directly opposite points and which are of sutlicient area to make good contact with the base and to carry the heavy currents required. The contact fingers are either resilient or resiliently mounted. and are spaced to engage firmly with the shell oi' the base placed between them. The contact fingers are movable into and out oi contact with the shell of the base, and in the preferred construction are opened l means 01" a finger cam 10 controlled by an arm 11 of which one end rides on the edge of the stationary cam disc 3. As clearly shown in Fig. 1, this cam disc 3 is so shaped that the contact fingers 9 are closed to engage the base while it is travelling from position Jr to position C and the cement is being baked, and are open during the remainder of its travel. The base cools very quickly after the current is shut ofi because the only mass of hot metal is the thin shell of the base. In some cases the finger cams 10 may be omitted, and the contact fingers mad-e stationary and sufiiciently resilient to permit the base to be thrust into place between them and into good electrical contact with them, thereby closing the circuit through the base. and to be pulled out from between them when the baking of the cement finished, thereby breaking the circuit, but as a rule it pr erable to close and open. the circuit by relative movement oi the contactfingers and the base.

The contact fingers 9 may be supplied with current in various ways, but I prefer to use step down transformers l2 ci'msisting of a secondary winding 13 oi comparativeiy low turns with its terminals connected directly to the contact fingers 9, and a prin'iary winding ll directly connected to slip rings supplied with current in all positions of the spider through a pair of brushes 16 mounted on they stationary ram disc 3 to engage the slip rings 15 and connected to a SL1]. ply circuit oi the usual commercial voltage.

In some cases it d :irable to provide 2 separate step down tra rmer for each pair of contact lingers as shown in 1 and 2, so as to avoid sl' ling contacts for carrying the heating turrent, which, for l as such as are commonly used on incar' scent lamps, may to advantage be of al at 100 ampcres at a potential of to 2 volts. ll ith such low voltages the connections should be as direct and of as low resistance as possible, and con sequently I prefer to connect the terminals ot the secondary winding directly to the contact fingers.

On a basing machine cmzstructed as shown in Fig. 1 for carrying out my invention the soldering of the leading-in wires to the bases may also be done. For example, at one po-1ition there may be mounted a side wire cutter and bender 17 for cutting and bending the side wire of the lamp into such position that it is close to the shell of the base; at a Flll).-.(- quent position a side solder device 18 for feeding the end of a solder wire to the ba e solder the side wire to the shell of the base; another position an automatic wire cutter if) for cutting the othe leadingin wire close to the center contact, and finally a. center contact soldering device 20 ctmstructcd as shown in my application S al llo. 19.129 filed March 28, 1925, and supplied with current from a transformer 21.

Though I prefer to connect ca :h pair of contact fingers 9 directly to the terminals of its own transformer 12 I may as shown diagrammatically in Fig. 3, provide connections such that all of the contact fingers 9 which are active are connected in seriesand supply the current from a single transform r 2. having its secondary winding connected to brushes 23 on the stationary cam 3 to engage the inner ends of the contact fingers 9. Bridging brushes 2% are mounted along the rim of the stationary cam 3 in position to connect in series all the contact fingers between the brushes 23.

As indicated diagrannnatically in Fig. at I may also supply the base in each of its several baking position with current by a pair of contacts each of said positions, the contacts and bases being moved relatively to each other by the rotation of the spider so that at each active or baking position the base is connected in circuit with the source of current, and is disconnected while the base is moving to the. next position. In each active position the base is supplied with current from bus bars 25, connected as shown, to brushes 26 mounted on the cam, disc 3 to engage the conta fingers which grip the base between them. Each pair of fingers is supp-lied with current through the stationary bi hes 26 in each po* sition as that pair or" fingers moves intermittcntly from position B to position C.

In Fig. 5 I have shown diagrammatically a transformer in which each pair of contact that all these secondary windings are in. proper relation to a common primary winding 28 supplied with current from the slip rings 15.

In Fig. 6 I have illustrated diagrammatically how the base may be heated inductively by means of a high frequency heating coil 29 supplied with high frequency current from a suitable source 30. This coil develops a rapidly varying electromagnetic field which induces sufficient current in the metal shell of the l use to heat the metal hot enough to bake the cement. This method of heating may be 'ne constructed substantially as l by replacing each pair of contact fingers 9 with a coil 29, these coils being supplied from any suitable source of high frequency current.

What I claim as new and desire to secure by Letters Patent of the United. States, is:

l. The method of cementing to a glass bulb a base comprising a shell of metal which consists in inter-posing between said bulb and shell in thermal relation to said shell a cement capable of bein hardened by baking and utilicing the electrical resistance of said shell. adjoining said cement to translate electrical. currents flowing in said shells into heat sufficient to bake said cement.

A device of the character described comprising means for holding a base with a metal shell in place on a glass bulb with. a layer of basing cement in contact with said shell and bulb and comprising insulated. fingers for engaging the metal shell of said base with a layer of basing cement between and in contact with said article and said metal, and electrical means for developing currents in he shell of said base to heat it while in said holder to bake said cement.

3. A device of the character described comprising a holder for holding a base with a metal shell in place on a bulb with a layer of basing cement interposed and comprising a pair of metal. fingers insulated from each other and positioned to engage the shell of said base, and electrical means cooperating with said base in said holder to pass through said metal shell a current great enough to heat it due to its electrical resistance and thereby bake said cement.

4. A. device of the character described comprising a holder for a tnlnilar metal object, a pair of contacts for engaging said object in said holder, a source of current connected to said contacts, and means for controlling the flow of current through said object.

A basing machine comprising means for holding a base having a metal shell positioned on a bulb, electrical contacts for engaging said base, and means for parsing current through said base between said contacts to develop heat in the metal of the base.

A device of the character described com prising a bulb holder, a cooperating base holder for holding a metal shell base in place on the bulb, a pair of contacts mova le relatively to said base holder for en ing the metal shell of the base in said hnder when in circuit closing position, a transformer ha ing terminals electrically connected to said contacts, and neans for producing relative movement of said contacts and said base holder to bring said contacts into and out of circuit closing position.

7. A. basing machine comprising a movable base holder, a pair of relatively movable contacts for engaging a base in said base holder, a source of current connected to said contacts, and means controlled by said movable base holder to open and close said contacts.

8. Abasing machine comprising a movable base holder ha 'ing ele trical contacts for engaging the shell of a base in said holder, a source of current, and means actuated by movement of said holder to control a circuit through said contacts and said base.

9. A basing machine comprising a rotatable carrier, a base holder mounted on and insulated from said carrier to hold a base on a bulb, contact fingers mounted to engage a base in said holder, a step down transformer mounted on said carrier to travel with said holder and having its secondary terminals directly connected to said contact fingers, and means responsive to the movement of said car .ier for controlling the flow of current through said contact fingers and the 10. A basing machine comprising a movable carrier, a plurality of base holders on said carrier, contact fingers associated with said holders for establishing an electrical circuit through the metal of a base held in said holder. means 1' it. for maintaining a closed electric circuit through the cm-Jtacts and the base in each holder during the ciuiiuetl portio of the travel of said means tor supplying current to .1.

12. In a basin; machine, the ot' a movable carrier luv-711.11

' combination 1 plurality of ase holders, a pair of en tat-ts associated with each holder to establish a ci rcuit through a base in said holder, a source of current. and connections whereby said contact-2 and the bases in said holders are ctnmected in the same circuitduring the travel of each ho through a predetermined "portion of its pad).

13. A basing machine comprising rotatable spider. heads on said spider for holding a bulb and base in proper relation for basing; contacts associated with each holder to establish a circuit through a base in said holder. 21 source of current connected to each pair of contacts. actuating means associated with said contacts and respoiu ive to movement of said spider for n a Iain ng each pair of contacts in engagement w" a base during a predetermined portion of the travel of the base and out of engg ement nith it during the re m portion ot its travel. wire working devices positioned adjacent the path of each holder to position one wire adjoining the base shell and to cut the other wire. soldering devices positioned adjacent the path of aid holders to solder on lv ing-in wire to the shell of the base in one position and the other leading-in wire to the center contact in another position of the holder, and common driring means for actuating said spider intermittently and sait devices while the spider is stationary.

l. A device of the character descriJed comprisimr a holder for maintaining a article ji .ttaposed to a mass of metal having in thermal relation to it a layer of cement capable of being hardened by heaing with said eemen in Contact with said article, and means associated with saic. holder for passing an electric current through said metal to develop in it sutlicient heat to harden said cement.

15. ll device of the character described comprising a holder for maintaining glass article juxtaposed to a mass of metal having in thermal relation to it a layer of cement capable of being hardened by heating with said cement in contact with said article, contacts for engaging said mass of metal at different points, and a source of current connected to said contacts.

16. A device of the character described comprising a movable holder for maintaining a glass article juxtaposed to a mass of metal having in thermal relation to it a layer of cement capable oi being hardened by heating with said cement in contact with said article, contacts for engaging said mass of metal at dillerent points, and a source of current consaid contacts during the travel of said holder.

In witness whereof, I have hereunto set my hand this 29th day of March 1926.

DANIEL K. \VRIGHT. 

